This invention relates to the labeling of objects by the use of heat to transfer design prints from a carrier to the objects being labeled.
In heat transfer labeling, a design print that is affixed to a carrier by a release layer is brought into contact with an object to be labeled. When heat is applied to the carrier the release layer becomes molten and permits the design print to become adhered to the object.
In the typical heat transfer label, as exemplified by U.S. Pat. No. 3,616,015, which issued Oct. 26, 1971, the release layer is a coating of wax on the carrier and the design print is in a transfer layer that is printed on the wax coating. With such a label, the application of heat during the transfer process causes a film of wax to be deposited over the entire region where the carrier is in contact with the object being labeled. The deposited film is of random configuration and is frequently much larger than the design print.
Although the wax film is transparent and generally not noticeable by casual observation, under certain lighting conditions the film is viewable and can present an objectionable appearance. The resulting film can be regarded as an expanded, irregular "halo" that surrounds the design print. Not only can the irregular halo present an objectionable appearance, it represents a wastage of material. Moreover, because of the tendency of the wax to penetrate the carrier material used in ordinary heat transfer labeling, a substantial amount of wax material is needed to form the transfer coating.
Accordingly it is an object of the invention to expedite and facilitate the heat transfer labeling of objects.
Another object of the invention is to improve the appearance of heat transfer labels. A related object is to eliminate the enlarged, irregular halo often encountered in heat transfer labeling.
A related object is to economize on the amount of material needed for the release layer in the heat transfer labeling of objects.